This proposal aims to examine presentation of chlamydial antigens by unaltered human cells. How humans present chlamydial antigens will determine which immune functions if any are stimulated. In contrast to Project 1 which will investigate the fine specificity of antigen presentation using lymphoblastoid cell lines, the work proposed in this project, Project 2, will study how antigen presentation takes place in human cells, with particular attention to the local immune response. Cells will be obtained from individuals previously infected with chlamydia. Two cell types will be studied. First, professional antigen presenting cells, monocytes, will be isolated from peripheral blood, incubated with live UV-inactivated, or heat-killed elementary bodies from chlamydia (Serovar E). Evidence for antigen presentation by class I and class II major histocompatibility complex (MHC) proteins will be sought using monoclonal antibodies directed against the MHC to block blastogenesis of nylon-wool purified T cells. The second cell type which will be examined is the endometrial epithelial (ENDEP) cell, a natural host cell for chlamydia, whose ability to present antigen is unknown. Cells will be polarized, grown in the presence of estrogen, and incubated with EB (live or inactivated with UV light or heat. Antigen presentation will be examined by testing T cell blastogenesis. If antigen presentation is observed, the class of MHC will be defined. Whether or not presentation of chlamydial antigens is observed, the effect of cytokines including IL-1, alpha and gamma interferon, and TNF alpha on presentation will be examined. The phenotype and cytokine profiles of responder lymphocytes for monocyte and ENDEP presentation will be compared. In addition, the effects of chlamydial infection on MHC expression will be examined. Lastly, using MOMP as a prototype, introduction of peptide antigens to antigen presenting cells will be altered to optimize presentation by one class or the other to elicit a particular responder response. Antigen modification may improve the protection of antichlamydial peptide vaccines. The proposed studies promise to increase not only understanding of the chlamydial immune response but also the immune response of the female genital tract, observations which may be useful not only in chlamydial infections but in other sexually transmitted diseases as well.